Segmented Information (Geographic Information of Long-lived Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	$ 486,599	$ 526,581
Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	486,599	526,581
United States [Member] | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	260,489	275,628
Canada [Member] | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	100,983	116,833
Europe [Member] | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	77,496	82,795
Other [Member] | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	$ 47,631	$ 51,325